Macron said leaders - jolted by graphic reports of slavery and brutal conditions – would boost support for the International Organization of Migration (IOM) "to help the return of the Africans who want it to their home countries."
Ninety percent of migrants intent on reaching Europe converge on Libya, says the UNHCR refugee agency, with tens of thousands stalled indefinitely by Italian-backed Libyan coastguard operations to deter often deadly Mediterranean crossings.
To tackle trafficking, the EU, African Union and the UN also said they would create a policing and intelligence task force to probe slave-trading, dismantle networks and funding, and protect migrants along routes.
The measures were agreed after Abidjan summit host Ivory Coast President Alassane Ouattara called for "all urgent measures" to end slave trading and other abuses in Libya.
It was a "wretched dram which recalls the worst hours of human history," he said.
Camps to be identified
Macron said Libya's UN-backed Tripoli-based government headed by President Fayez Sarraj had "restated its agreement to identify the camps where barbaric scenes have been identified."
"This work will be carried out in the next few days, in line with the [migrants'] countries of origin," he said, adding that Sarraj would grant access to agencies such as the IOM and the UNHCR.
German delegation sources also said Sarraj had agreed his government would enable access.
The German news agency DPA also reported that African nations would take the leading roles in identifying the each migrant's country of origin and issuing travel documents. Africans would also pay a large portion of transport.
EU nations would provide repatriation and fresh-start assistance so that those returning home would not lose face, reported DPA.
Transfers to Chad and Niger would be run by the UNHCR for those migrants seeking shelter from political persecution or civil war in their home countries.
From those two locations, further transfers were foreseen to nations willing to accept them, either in the EU or nations outside Europe.
Nigerian President Muhammadu Buhari said all Nigerians stranded in Libya and other parts of the world would be brought home and "rehabilitated."
It was appalling that "some Nigerians were being sold like goats for a few dollars in Libya," said Buhari, adding that so far this year 4,000 had "safely returned home."
Support 'very important'
German Chancellor Angela Merkel, who in August had already pledged assistance, said it was "very important" to support Africans so people did not suffer in "horrible camps in Libya."
Many Africans head to Europe, risking desert and maritime crossings, saying high unemployment and climate change leave them with little choice.
African Union Commission Chairman Moussa Faki Mahamat said Africa and Europe did not have much of a future without "heavy investment in this youth, its education, its training."
On its closing day, Thursday, summit leaders will focus on how to provide stability for a continent likely to more than double its population to 2.4 billion by 2050.
ipj/rc (AP, Reuters, AFP, dpa)